This project utilizes the scid hu mouse to explore HIV 1 induced dysfunction and/or destruction of the central human hematolymphoid microenvironment. This project will analyze whether HIV 1 infection suppresses multilineage and/or lineage committed human hematopoiesis in the scid hu Thy/Liv and Bone models, and will assess the mechanism, i.e. direct infection or indirect cytokine mediated suppression of hematopoiesis. The last aim of the project will ask whether similar mechanisms may be operative in symptomatic or asymptomatic HIV 1 infected individuals.